Vehicle Rotating Electric Machine

ABSTRACT

An inverter device is mounted on the rotating electric machine body The inverter device includes a module unit having a converter circuit and a control unit that controls the operation of the converter circuit. The converter circuit is configured by connecting a plurality of the following series circuits in parallel, each of the series circuits includes a P-channel MOS semiconductor device disposed at a higher potential side and an N-channel MOS semiconductor device disposed at a lower potential side which are electrically connected in series. An electric power that is supplied from a battery or an electric power that is supplied to the battery is controlled.

CLAIM OF PRIORITY

The present application is a continuing application of U.S. applicationSer. No. 11/102,627, filed Apr. 12, 2005, which issued on Apr. 24, 2007,as U.S. Pat. No. 7,208,918.

The present application also claims priority from Japanese applicationserial no. 2004-117027, filed on Apr. 12, 2004, and serial no.2005-033760, filed on Feb. 10, 2005, the contents of which are herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

The present invention relates to a vehicle rotating electric machine tobe mounted on a vehicle.

For the purpose of improving fuel consumption and reducing an exhaustemission including carbon dioxide, in vehicles, there has been proposedan idling stop system for stopping an engine temporarily when theautomobile are stopping such as waiting at a red light. The idling stopsystem provides an engine start system including, for example, a motorand an inverter device, separately from a starter. In this type, themotor is disposed in proximity to the engine, and transmits a drivingforce to the engine through a clutch and a belt at the time ofrestarting the engine. On the other hand, since the inverter device hasa large number of electronic parts that are low in the durability athigh temperature, it is necessary that the inverter device is separatedand arranged at a position that avoids a high temperature environment inthe vicinity of the engine. For that reason, additional parts such asthe inverter device and the electric cable that connects the inverterdevice and the motor are disposed within an engine room having a limitedspace, and the idling stop system cannot be mounted without changing thelayout of the interior of the engine room.

From the above viewpoint, a motor and an inverter device able to besimply mounted and low in the costs have been demanded for spread of theidling stop system. As one solution to the above demand, there has beenproposed an alternator (hereinafter also referred to as “inverterbuilt-in alternator”) which is equipped with a three-phase bridgeconverter circuit using MOS (metal oxide semiconductor) elements and acontrol circuit for the three-phase bridge converter circuit to enablemotor drive. The inverter built-in alternator has an inverter circuit inwhich a rectifier diode of a normal vehicle alternator is replaced by aMOS element. Since the inverter built-in alternator can be realized bythe substantially same size as that of the normal vehicle alternator,the idling stop system can be realized without remarkably changing thelayout of the interior of the engine room even in a small vehicle havinga limited mounting space. Documents of the prior arts are as follows.

[Document 1] Japanese Patent Laid-Open No. 2002-89417

[Document 2] Japanese Patent Laid-Open No. H6(1994)-225476

[Document 3] Japanese Patent Laid-Open No. H7(1995)-75262

[Document 4] Japanese Patent Laid-Open No. 2003-70256

In the inverter circuit equipped in the inverter built-in alternator,downsizing of the device and having the durability at a high temperatureare required to enable to arrange the device concerning the inverter ina high temperature environment in the vicinity of the engine. However,because the conventional large current output inverter has thethree-phase bridge converter circuit made up of an N-channel MOSFET(metal oxide semiconductor field effect transistor) which is low in theon-resistance, there is provided a wiring layout in which the MOSFET atthe higher side and the MOSFET at the lower side are connected toconductor plates that are different in the potential. As a result,because the two conductor plates thus insulated are required, theinverter circuit is prevented from being downsized. Also, because thepotential of the output terminal of the bridge circuit fluctuatesroughly from the power potential to the ground potential according tothe on/off states of the semiconductor switches at the higher side andthe lower side, a power supply that provides a reference potential asthe output terminal potential is required in the driver circuit of theMOSFET at the higher side in each of the phases (refer to FIG. 15). Alarge-capacity electrolytic capacitor is essential for the power supplyof the driver circuit of the high-side MOSFET in order to hold thevoltage. However, the electrolytic capacitor is larger in the volumethan other electronic parts, and has such a characteristic that theelectrostatic capacity is reduced and the deterioration such as anincrease of the internal resistor is liable to occur under the hightemperature environment. As a result, it is difficult to realize theinverter built-in alternator that requires the downsizing and thehigh-temperature durability in the inverter circuit that requires theelectrolytic capacitor.

Also, the inverter built-in alternator requires the driver circuit, theminimum control circuits, a protector circuit and power supplies forthose circuits in addition to the field current control circuit that isequipped in the conventional alternator having only a power generatingfunction. However, in the case where the respective circuits are made upof the individual parts, it is very difficult from the viewpoint ofsizes to realize that those circuits are equipped in the inverterbuilt-in alternator. In addition, there is required that each of thosecircuits is made up of a circuit or a power supply which does notrequire the electrolytic capacitor from the viewpoint of thehigh-temperature resistant durability.

SUMMARY OF THE INVENTION

The present invention provides a vehicle rotating electric machine thatis capable of realizing that a power converter device is mounted on arotating electric machine body by about the same built-structure as theconventional one.

In order to provide the vehicle rotating electric machine, the presentinvention improves the property of mounting the power converter deviceonto the rotating electric machine body. As one of specific solvingmeans, the power control circuit is configured by connecting a pluralityof the following series circuits in parallel, each of the seriescircuits includes a P-channel MOS semiconductor device disposed at ahigher potential side and an N-channel MOS semiconductor device disposedat a lower potential side which are electrically connected in series.

Also, the present invention integrates a plurality of electronic circuitelements that constitute a control circuit and a driver circuit in acontrol unit that controls the operation of the power control circuit.

According to the present invention, since the inverter device can bedownsized, there can be realized the vehicle rotating electric machinein which the inverter device is mounted on the rotating electric machinebody by the substantially about same size as that of the general vehiclealternator. As a result, even in the small vehicle having a limitedmounted space, the idling stop function can be provided withoutremarkably changing the layout of the interior of an engine room.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a semiconductor device mounting structureof a converter circuit in an inverter device that is integrally mountedon a motor-alternator which is an embodiment of the present invention.

FIG. 2 is a plan view showing a mounting structure of the inverterdevice that is integrally mounted on the motor-alternator which is theembodiment of the present invention.

FIG. 3 is a cross-sectional view showing the entire structure of themotor-alternator according to the embodiment of the present invention.

FIG. 4 is a block diagram showing the system structure of themotor-alternator according to the embodiment of the present invention.

FIG. 5 is a block diagram showing the functional structure of a controlcircuit shown in FIG. 4.

FIG. 6 is a block diagram showing the functional structure of a drivercircuit shown in FIG. 4.

FIG. 7 is a block diagram showing the circuit structure of a convertercircuit shown in FIG. 4.

FIG. 8 is a block diagram showing the circuit structure of a fieldcircuit shown in FIG. 4.

FIG. 9 is a circuit structural diagram showing the circuit structure ofa driver unit of the driver circuit shown in FIG. 6.

FIG. 10 is a block diagram showing the structure of a power train of anautomobile on which the motor-alternator that is the embodiment of thepresent invention is mounted.

FIG. 11 is a flowchart showing the operation of the motor-alternatoraccording to the embodiment of the present invention.

FIG. 12 is a plan view showing the semiconductor device mountingstructure of a converter circuit in an inverter device according to acomparative example.

FIG. 13 is an explanatory diagram showing a system of driving a motor bysubjecting the switching semiconductor device to one on/off operation inone cycle.

FIG. 14 is a circuit diagram showing the inverter device according tothe embodiment of the present invention.

FIG. 15(1) is a circuit diagram in a case where an n-MOS and an n-MOSare combined together, and FIG. 15(2) is a circuit diagram in a casewhere a p-MOS and an n-MOS are combined together.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described withreference to FIGS. 1 to 11. A motor-alternator 100 according to anembodiment of the present invention is a so-called inverter built-invehicle rotating electric machine in which an inverter device 50 isintegrated with a rotating electric machine body 1, and constitutes anelectric power train of an automobile 200.

The automobile 200 to which the motor-alternator 100 of the presentinvention is applied is a so-called hybrid automobile having both of anengine power train with an internal combustion engine as a power sourceand an electric power train with the motor-alternator 100 as a powersource, as shown in FIG. 10. The engine power train is mainly used for adriving power source of the automobile 200. The electric power train ismainly used for the power source to make starting of the engine 120, andused for the electric power supply for the automobile 200. Theautomobile 200 having such an electric power train, when the automobilestops such that the automobile waits at a red light in a state where theignition key is on, the engine 120 automatically stops, and when theautomobile starts, the electric power train automatically makes theengine start for starting of the vehicle. Thereby the automobile makesit possible to perform so-called idling stop driving which enables thefuel consumption of the automobile 200 to be improved and the exhaustemission to be reduced.

As shown in FIG. 10, a front axle 115 is rotatably supported at a frontside of a vehicle body. Front wheels 111 and 112 are disposed at bothends of the front axle 115. A rear axle 116 is rotatably supported at arear side of the vehicle body. Rear wheels 113 and 114 are disposed atboth ends of the rear axle 116. A differential gear 117 that is a powersharing mechanism is disposed in the center of the front axle 115. Thedifferential gear 117 shares a rotational driving force, which has beentransmitted through a transmission 130 from the engine 120, to the rightand left axle members of the front axle 115. The transmission 130 variesthe rotational driving force of the engine 120 and transmits the varieddriving force to the differential gear 117. The driving of the engine120 is controlled by controlling the operations of accessories such asan injector that is a fuel control mechanism and a throttle valve thatis an air flow rate control mechanism with an engine control device 140.

The motor-alternator 100 is arranged within the engine room at the frontof the vehicle body 110 together with the engine 120, and mounted to theside of the engine 120 and mechanically connected to the engine 120. Themechanical connection can be realized by looping a belt 170 over apulley 120 a disposed on a crank shaft of the engine 120 and a pulley100 a disposed on the rotary shaft of the motor-alternator 100. As aresult, the motor-alternator 100 can transmit the rotational drivingforce to the engine 120, and can receive the rotational driving forcefrom the engine 120.

The electric power train of the automobile 200 is electrically connectedto a 14 V vehicle power supply comprising a battery 150 as shown inFIGS. 4 and 10, and gives a power generated by itself to the battery orreceives a power from the 14 V vehicle power supply. The 14 V vehiclepower supply is electrically connected with a starter as a startingdevice of the engine 120, and vehicle accessories machinery such aslamps, a car radio, and direction indicators not shown. A lead batteryof an output voltage of about 12 V is used for the battery 150.

As described above, the motor-alternator 100 is structured such that theinverter device 50 is integrated with the rotating electric machine 1.In the motor-alternator 100, the rotating electric machine 1 is made upin common with conventional alternators mounted on the automobile asshown in FIG. 3. More specifically, the rotating electric machine 1comprises a stator 2 having a stator winding 5 and a rotor 3 having afield winding 8 as shown in FIG. 4. A specific structure of the rotatingelectric machine body 1 will be described later with reference to FIG.3. A three-phase alternating power, which is controlled by the inverterdevice 50, is supplied to the stator winding 5. A field current, whichis also controlled by the inverter device 50, is supplied to the fieldwinding 8. In the motor-alternator 100, a rotating magnetic field isgenerated by such three-phase alternating power and field current, andthe rotor 3 rotates with respect to the stator 2. As a result, the motorgenerator 100 operates as an electric motor, and generates a rotationaldriving force for starting the engine 120. On the other hand, in themotor-alternator 100, when a field current is supplied to the fieldwinding 8, and the rotor 3 rotates by the rotational driving force ofthe engine 120, a voltage is induced in the stator winding 5. As aresult, the motor-alternator 100 operates as an alternator, andgenerates a three-phase alternating power to charge the battery 150. Inthis embodiment, a synchronous alternating rotating electric machine isused for the motor-alternator 100. However, an inductive alternatingrotating electric machine may be used as the motor-alternator 100.

The inverter device 50 is a power converter device that converts a DCpower supplied from the battery 150 into a three-phase AC power, orconverts a three-phase AC power obtained by the power generation of themotor-alternator 100 into a DC power. More specially, the inverterdevice 50 comprises a module unit 52 and a control unit 51 as shown inFIG. 4. The mounting structure of the inverter device 50 will bedescribed later with reference to FIG. 1. The module unit 52 has aconverter circuit 55 and a field circuit 56. The converter circuit 55 isa power control circuit that converts a DC power supplied from thebattery 150 into a three-phase AC power, or converts a three-phase ACpower supplied from the stator winding 5 into a DC power. The fieldcircuit 56 is a field current control circuit that controls the fieldcurrent supplied to the field winding 8 from the battery 150. Thecontrol unit 51 has a control circuit 53 and a driver circuit 54. Thecontrol circuit 53 is a control logic circuit that outputs, to thedriver circuit 54, command signals to control the operation of theconverter circuit 55 and the field circuit 56 according to a commandsignal from a host control device, for example, the engine controldevice 140, and various detection signals (feedback signals) related toa phase voltage of the motor-alternator 100 or the terminal voltage ofthe battery 150. Upon receiving the command signal from the controlcircuit 53, the driver circuit 54 outputs the driving signals to operatethe converter circuit 55 and the field circuit 56 to the convertercircuit 55 and the field circuit 56. In order to improve the mountingproperty of the inverter device 50 on the rotating electric machine body1, in this embodiment, a voltage adjuster that has been mounted on thevehicle alternator up to now is integrated with the inverter device 50to ensure a space where which the inverter device 50 is mounted.

The respective structures of the control circuit 53, the driver circuit54, the converter circuit 55 and the field circuit 56 in the inverterdevice 50 will be described in more detail.

The converter circuit 55 converts the DC power into the three-phase ACpower or the three-phase AC power into the DC power by the switching(on/off) operation of the switching semiconductor device. The switchingsemiconductor device may be MOSFETs (MOS field effect transistor) thatare MOS (metal oxide semiconductor) elements, or an IGBT (insulated gatebipolar transistor). In this embodiment, MOSFETs in which respectivediodes are incorporated are used for the switching semiconductor device.As shown in FIG. 7, the converter circuit 55 is configured with a bridgecircuit of 6 phases (3 phases×the number of stator windings:2) in whicheach thereof has a P-channel MOSFET and a N-channel MOSFET. In each(arms) of the 6 phases, a drain electrode of the P-channel MOSFET 64 anda drain of the N-channel MOSFET 65 are electrically connected to eachother in series, on condition that the P-channel MOSFET 64 is disposedat a higher potential pole (positive pole) side, and the N-channelMOSFET 64 is disposed at a lower potential pole (negative pole) side.And by connecting the respective phases (series circuits: arms) to eachother in parallel, the bridge circuit of 6 Phases is configured forconverter. A source electrode of the P-channel MOSFET 64 is electricallyconnected to the higher potential pole (positive pole) side in bothpoles of the battery 150. A source electrode of the N-channel MOSFET 65is electrically connected to the lower potential pole (negative pole)side in both poles of the battery 150. Phase windings of the statorwinding 5 respectively are electrically connected between the drainelectrodes of the P-channel MOSFET 64 and the N-channel MOSFET 65. Thatis, a U-phase winding on one side of the stator winding 5 iselectrically connected between the drain electrodes of the P-channelMOSFET 64U₁ and the N-channel MOSFET 65U₁. A U-phase winding on theother side of the stator winding 5 is electrically connected between thedrain electrodes of the P-channel MOSFET 64U₂ and the N-channel MOSFET65U₂. The same structure as the U phase is applied to a V-phase and aW-phase. Corresponding driving signals A to L are inputted from thecontrol unit 51 to the gate electrodes of the P-channel MOSFET 64 andthe N-channel MOSFET 65. A voltage between the drain electrodes of theP-channel MOSFET 64 and the N-channel MOSFET 65 is inputted to thecontrol unit 51 as a phase voltage signal. A voltage at a higherpotential pole (positive pole) side in both poles of the battery 150 isinputted to the control unit 51 as a battery positive pole voltagesignal.

The field circuit 56 controls a field current that flows into the fieldwinding 8 from the battery 150 due to the switching (on/off) operationof the switching semiconductor device. An N-channel MOSFET 69 is usedfor the switching element. The drain electrode of the N-channel MOSFET69 is electrically connected to a negative pole end of the field winding8 (a side opposite to the positive pole end connected to the higherpotential (positive pole) side of the battery 150). A source electrodeof the N-channel MOSFET 69 is electrically connected to the lowerpotential (negative pole) side of the battery 150. A driving signal Tfrom the control unit 51 is inputted to a gate electrode of theN-channel MOSFET 69. A diode 68 is electrically connected between thedrain electrodes of the N-channel MOSFET 69 and the higher potential(positive pole) side of the battery 150. The diode 68 is made up of aP-channel MOSFET which is in a forward direction toward the higherpotential (positive pole) side of the battery 150 from the drainelectrode side of the N-channel MOSFET 69.

The control circuit 53 is a circuit that operates by a driving voltageof about 5 V, and includes plural control units as shown in FIG. 5. Thedriving voltage is applied from the driver circuit 54 which will bedescribed later, and the driving voltage results from stepping down thevoltage (about 12 V) of the battery 150. The control circuit 53 inputs acommand signal from the engine control device 140 that is a host controldevice. The command signal from the engine control device 140 is asignal for operating the motor-alternator 100 as a motor, or a signalfor operating the motor-alternator 100 as an alternator. Those signalsare outputted according to the operation state of the vehicle. Forexample, in the case of starting the engine 120 to start the vehiclefrom a stopping state of the vehicle, such a mode of changing from theidle stop to starting of the engine 120, the engine control device 140outputs a start signal for operating the motor-alternator 100 as themotor to the control circuit 53 when the off of the brake is detected.

The transmission of the command signal from the engine control device140 to the control circuit 53 is conducted by means of an LIN (localinterconnect network) system which is one of the serial communicationsystems. The command signal from the engine control device 140 to thecontrol circuit 53 through a LIN is inputted to a microprocessor(hereinafter referred to as “MP”) 53 d through an interface circuit 53f. The MP 53 d judges the operation mode of the motor-alternator 100based on an inputted command signal, and outputs the operation commandsto the respective control units according to the operation mode so thatthe respective control units execute given processing corresponding tothe operation mode. Also, the MP 53 d reads program or datacorresponding to the operation mode from a RAM 53 m that is a memorydevice that can rewrite the stored information or a ROM 53 n that is amemory device that can read the stored information, or writes the datain the RAM 53 m. In addition, the MP 53 d has an A/D converter 53 k anda timer/counter 53 e. The AD converter 53 k converts an analog quantitysuch as a voltage or temperature inputted to the MP 53 d into a digitalquantity. A timer/counter 531 is used to, for example, measure a timewidth at which the command value is sequentially changed by the controlprogram and a time interval in which the LIN communication is conducted.As a result, the MP 53 d can detect the rotation speed of themotor-alternator 100, and can output the predetermined operationcommands to the respective control units by comparing the sensedrotation speed with a predetermined rotation speed. The signaltransmission between the engine control device 140 and the controlcircuit 53 is executed by using the LIN, thereby making it possible toreduce the number of communication lines between the engine controldevice 140 and the control circuit 53.

The control unit has a motor control unit 53 a, an alternator(synchronous rectifier) control unit 53 b, and a filed control unit 53h.

When the motor-alternator 100 operates as the motor, the motor controlunit 53 a outputs voltage command signals to control the operation ofthe P-channel MOSFETs 64 and the N-channel MOSFETs 65 of the convertercircuit 55. An operation command signal from the MP 53 d, a rotationspeed signal from the rotation speed calculating circuit 53 e, and phasevoltage signals c to h from the converter circuit 55 are inputted to themotor control 53 a through the driver circuit 54. The rotation speedsignal is calculated based on a sensed signal b from a rotation sensor73. The motor control unit 53 a outputs voltage command signals forcontrolling the operation of the P-channel MOSFETs 64 and the N-channelMOSFETs 65 according to the operation command signal from the MP 53 dand based on the sensed signal b from the rotation sensor 73. Thevoltage command signals are to control the MOSFETs 64, 65 so that themotor-alternator 100 reaches a target rotation speed. In the voltagecommand signals from the motor control unit 53 a, the voltage commandsignals related to the P-channel MOSFETs 64 at the higher potential sideare inputted to a switching circuit 53 j. The voltage command signalsrelated to the N-channel MOSFETs 65 s at the lower potential side areinputted to a switching circuit 53 i.

When the motor-alternator 100 operates as the alternator, the alternator(synchronous rectifier) control unit 53 b outputs voltage commandsignals to control the operation of the P-channel MOSFETs 64 and theN-channel MOSFETs 65 of the converter circuit 55. The operation commandsignal from the MP 53 d, the phase voltage signals c to h from theconverter circuit 55 via the driver circuit 54, a battery higherpotential side voltage signal i from the converter circuit 55 via thedriver circuit 54, and a battery lower potential side voltage signal jfrom the driver circuit 54, are inputted to the alternator (synchronousrectifier) control unit 53 b. The alternator (synchronous rectifier)control unit 53 b outputs voltage command signals for controlling of theoperation of the P-channel MOSFETs 64 and the N-channel MOSFETs 65, inorder to synchronously rectify the three-phase AC power from themotor-alternator 100 and convert the AC power into a DC power accordingto the operation command of the MP 53 d. In this case, the alternatorcontrol unit 53 b compares a voltage across both ends of the battery 150with the inputted phase voltage values of the respective phases (in thecase where the phase voltage is positive, the phase voltage value iscompared with the battery higher potential side voltage, whereas in thecase where the phase voltage is negative, the phase voltage value iscompared with the battery lower potential side voltage). Then, thealternator (synchronous rectifier) control unit 53 b outputs voltagecommand signals for controlling the operation of the P-channel MOSFETs64 and the N-channel MOSFETs 65 according to the comparison result beingequal to or more than a predetermined voltage (forward voltage drop ofthe diode: about 0.7 V), or less. In the voltage command signals fromthe alternator (synchronous rectifier) control unit 53 b, the voltagecommand signals related to the P-channel MOSFETa 64 at the higherpotential side are inputted to the switching circuit 53 j. The voltagecommand signals related to the N-channel MOSFET 65 at the lowerpotential side are inputted to the switching circuit 53 i.

When the motor-alternator 100 operates as the motor or the alternator,the field control unit 53 h outputs a voltage command signal to controlthe operation of the N-channel MOSFET 69. The N-channel MOSFET is usedto pass a field current through a winding 8 of the field circuit 56. Theoperation command signal from the MP 53 d and an abnormality signal froma detector/protector circuit unit 53 c that will be described later, areinputted to the field control unit 53 h. When the motor-alternator 100operates as the motor, the field control unit 53 h calculates a fieldcurrent value based on the operation command from the MP 53 d so that apredetermined torque is outputted from the motor-alternator 100. And thefield control unit 53 h calculates a voltage command value based on thecalculated field current value; then, it outputs the voltage commandvalue as a voltage command signal for controlling the operation of theN-channel MOSFET 69. When the motor-alternator 100 operates as thealternator, the field control unit 53 h calculates a field current valueaccording to the operation command of the MP 53 d so that apredetermined electrical energy is outputted from the motor-alternator100. And the control unit 53 h calculates the voltage command valuebased on the calculated field current value; then, the field controlunit 53 h outputs the voltage command value as the voltage commandsignal for controlling the operation of the N-channel MOSFET 69. Also,when a damp surge voltage or the like is detected by thedetector/protector circuit unit 53 c, the field control unit 53 houtputs the voltage command signal to control the operation of theN-channel MOSFET 69 based on the abnormality signal from thedetector/protector circuit unit 53 c so that the amount of currentflowing in the winding 8 is decreased. A voltage command signal x fromthe field control unit 53 h is inputted to the driver circuit 54.

The detector/protector circuit unit 53 c is used to detect thegeneration of an over-voltage such as a damp surge voltage, anover-current or an over-temperature, and protect a switching element ofthe converter circuit 55 or the field circuit 56 from such over-voltage,over-current or over-temperature. An operation command signal from theMP 53 d, phase voltage signals c to h from the converter circuit 55 viathe driver circuit 54, a battery higher potential side voltage signal ifrom the converter circuit 55 via the driver circuit 54, and a batterylower potential side voltage signal j from the driver circuit 54, areinputted to the detector/protector circuit unit 53 c. Thedetector/protector circuit unit 53 c executes various abnormalitydetections on the basis of the operation command signal from the MP 53d. As a result, if there is an abnormality, the detector/protectorcircuit unit 53 c outputs the abnormality signal to the MP 53 d and thefield control unit 53 h. For example, in the case where the damp surgevoltage is detected by the detector/protector circuit unit 53, theoperation command signal is outputted to the switching circuit 53 i sothat the N-channel MOSFET 65 at the lower potential side of theconverter circuit 55 should be turned off.

The switching circuit 53 j switches between the voltage command signalsfrom the motor control unit 53 a and the voltage command signals fromthe alternator (synchronous rectifier) control unit 53 b according tothe operation mode of the motor-alternator 100; and the switched signalsare outputted. Those voltage command signals are used for controllingthe operation of the P-channel MOSFET 64. The operation command signalfrom the MP 53 d and the voltage command signals from the motor controlunit 53 a or the alternator (synchronous rectifier) control unit 53 b,are inputted to the switching circuit 53 j. The switching circuit 53 jswitches the outputs of the voltage command signals for the P-channelMOSFET 64 according to the operation command signal from the MP 53 d,and outputs the switched voltage command signals to the driver circuit54 as the voltage command signals j to q.

The switching circuit 53 i switches between the voltage command signalsfrom the motor control unit 53 a and the alternator (synchronousrectifier) control unit 53 b according to the operation mode of themotor-alternator 100; and the switched signals are outputted. Thosevoltage command signals are used for controlling the operation of theN-channel MOSFET 65. The operation command signal from the MP 53 d andthe voltage command signals from the motor control unit 53 a or thealternator (synchronous rectifier) control unit 53 b, are inputted tothe circuit 53 i. The switching circuit 53 i switches the outputs of thevoltage command signals for the N-channel MOSFET 65 according to theoperation command signal from the MP 53 d, and outputs the voltagecommand signals to the driver circuit 54 as the voltage command signalsr to w.

In this embodiment, as shown in FIG. 5, the motor control unit 53 a, thealternator (synchronous rectifier) control unit 53 b, and thedetector/protector circuit unit 53 c are surrounded by a dotted line.This indicates that the phase voltage signals c to h, the battery highpotential side voltage signal i, and the battery low potential sidevoltage signal j, are commonly inputted to the motor control unit 53 a,the alternator (synchronous rectifier) control unit 53 b, and thedetector/protector circuit unit 53 c in the control circuit 53. Arrowsindicative of signals that are commonly inputted to the motor controlunit 53 a, the alternator (synchronous rectifier) control unit 53 b andthe detector/protector control unit 53 c are inputted to the boxindicated by the dotted line. Also, the number of arrows of the voltagecommand signals from the motor control unit 53 a and the alternator(synchronous rectifier) control unit 53 b, respectively, is equal to thenumber of P-channel MOSFETs 64 and N-channel MOSFETs 65, that is 12. Inthis embodiment, for simplification of the drawing, those arrows areindicated by one arrow. In addition, in this embodiment, in order todistinguish between power flows and signal flows, the power flows areindicated by solid lines, and the signal flows are indicated by dottedlines, respectively.

The control circuit 53 is provided with a temperature sensor 53 g. Also,a thermistor 57 is disposed in the converter circuit 55, a sensingsignal from the termistor 57 is inputted to the control circuit 53. Inthe control circuit 53, any signal of the sensing signal from thetemperature sensor 53 g and the sensing signal from the thermistor 57 isselected and inputted to an A/D converter 53 k. Then, the signal isconverted into a digital signal and inputted to the MP 53 d.

The driver circuit 54 operates at an output voltage (about 12 V) of thebattery 150, and as shown in FIG. 6, comprises driver units 54 d ₁ to 54d ₁₂, 54 e, level converter circuits 54 b, 54 c, and a control powersupply 54 a. The control power supply 54 a is electrically connectedbetween both poles of the battery 150, and outputs a driving power ofthe control circuit 53. The control power supply 54 a supplies a controlpower k resulting from stepping down the output voltage (about 12 V) ofthe battery 150 to about 5 V to the control circuit 53. The driver units54 d ₁ to 54 d ₆ output driving signals to drive the P-channel MOSFET 64corresponding to the converter circuit 55. The driver unit 54 d ₇ to 54d ₁₂ output driving signals to turn on/off the N-channel MOSFET 65corresponding to the converter circuit 55. The driver unit 54 e outputsa driving signal to drive the N-channel MOSFET 65 of the field circuit56. The voltage command signals 1 to q among the voltage command signalsoutputted from the control circuit 53, are increased in the potentiallevel by the level converter circuit 54 d and then inputted to thecorresponding driver units 54 d ₁ to 54 d ₆. Likewise, the voltagecommand signals r to w are increased in the potential level by the levelconverter circuit 54 d and then inputted to the corresponding driverunits 54 d ₇ to 54 d ₁₂. The voltage command signal x from the controlcircuit 53 is increased in the potential level by the level convertercircuit 54 c and then inputted to the driver unit 54 e. The driver units54 d ₁ to 54 d ₆ output the driving signals A to F to the gate electrodeof the corresponding P-channel MOSFET 64 according to the inputtedvoltage command signals 1 to q. The driver units 54 d ₇ to 54 d ₁₂output the driving signals G to L to the gate electrode of thecorresponding N-channel MOSFET 65 according to the inputted voltagecommand signals r to w. The driver unit 54 e outputs the driving signalT to the gate electrode of the corresponding N-channel MOSFET 65according to the inputted voltage command signal x. The level convertercircuit 54 d drops the potential levels of the phase voltage signals Mto R and the battery higher potential side voltage signal S from theconverter circuit 55, and then output those signals to the controlcircuit 53 as the phase voltage signals c to h and the battery higherpotential side voltage signal i. In addition, the level convertercircuit 54 b takes in the lower potential side voltage of the battery150 as the battery lower potential side voltage signal, drops thepotential level and outputs the voltage to the control circuit 53 as thebattery lower potential side voltage signal j.

Each of the driver units 54 d ₁ to 54 d ₁₂ is made up of a circuitincluding a transistor and a resistor, as shown in FIG. 9. In thisexample, there is shown a structure of a driver unit for one arm whichconsists of a P-channel MOSFET 64 and an N-channel MOSFET 65. The driverunit for driving the P-channel MOSFET 64 is made up of the following anoff-circuit and an on-circuit. The off-circuit comprises a seriescircuit of a transistor 401 and a resistor 407, a series circuit of atransistor 402 and a resistor 408, and a series circuit of a transistor403 and a resistor 409; and the off-cut circuit is formed by connectingthese series circuits in parallel. The on-circuit is formed with aseries circuit of a transistor 413 and a resistor 414. The driver unitfor driving the N-channel MOSFET 65 is made up of the following anoff-circuit and an on-circuit. The off-circuit comprises a seriescircuit of a transistor 404 and a resistor 410, a series circuit of atransistor 405 and a resistor 411, and a transistor 406 and a resistor412; and the off-circuit is formed by connecting these series circuitsin parallel. The on-circuit is formed with the series circuit of atransistor 415 and a resistor 416. In the off-circuit of the P-channelMOSFET 64, each emitter electrode of the transistors 401-403 iselectrically connected to a source electrode side of the P-channelMOSFET 64, and each end of the resistors 407-409 opposite to eachcollector electrode of the transistors 401-403 is electrically connectedto a gate electrode side of the P-channel MOSFET 64. In the on-circuitof the P-channel MOSFET 64, an emitter electrode of the transistor 413is connected to a source electrode side of the N-channel MOSFET 65, andend of the resistor 414 opposite to a collector electrode of thetransistor 413 is connected to a gate electrode side of the P-channelMOSFET 64. In the off circuit of the N-channel MOSFET 65, each emitterelectrode of the transistors 404-406 is electrically connected to asource electrode side of the N-channel MOSFET 65, and each end of theresistors 410-412 opposite to each collector electrode side of thetransistor 404-406 is electrically connected to a gate electrode side ofthe N-channel MOSFET 65. In the on circuit of the N-channel MOSFET 65,an emitter electrode side of the transistor 415 is electricallyconnected to a source electrode side of the P-channel MOSFET 64, and anend of the resistor 416 opposite to a collector electrode side of thetransistor 415 is electrically connected to a gate electrode side of theN-channel MOSFET 65.

In the driver unit thus structured according to this embodiment, bychanging the off signal applied to the base electrodes of thetransistors 401 to 403 (off circuit of each P-channel MOSFET 64 switch),it possible to control a speed of drawing out the electric charges ofthe gate electrode of the P-channel MOSFET 64 according to theresistances of the resistors 407 to 409. For example, when it is assumedthat the resistances of the resistors 407 to 409 are 10Ω, 20Ω and 40Q,the resistances in the off circuit of the P-channel MOSFET 64 can beadjusted in a wide range of about 6 to 40Ω. According to thisembodiment, when the MOS elements for the converter circuit 55 arechanged, the switching speed of that element can be readily changed.Also, according to this embodiment, since the control circuit 53 has theMP 53 d, the RAM 53 m and the ROM 53 n, the off signal supplied to thebase electrode of the transistors 401 to 403(off circuit of theP-channel MOSFET 64) can be readily changed over by changing of thevariable of the memory. In addition, according to this embodiment, bychanging the program of the switching timing of the off signal that isapplied to the base electrode of the transistors 401 to 403, it possibleto perform soft switching for changing a speed depend on time at whichthe gate electric charges of the transistors 401 to 403 is drawn out.The same is applied to the N-channel MOSFET 65 side.

Subsequently, the actual structure of the motor-alternator 100 accordingto this embodiment will be described with reference to FIGS. 1 to 3.First, the structure of the rotary electric machine body 1 will bedescribed.

In FIG. 3, reference numeral 2 denotes a stator. The stator 2 has astator core 6 and a stator winding 5 installed on the stator core 6. Thestator core 6 is formed of a cylindrical lamination core resulting fromforming a plurality of annular core plates each of which is obtained bypunching a thin silicon steel plate. The thickness of each of the coreplates laminated at both ends of the lamination core in the axialdirection is thicker than the core plates laminated in the middleportion in the axial direction. A core back (not shown) is formed on theouter peripheral portion of the stator core 6 is formed with. The coreback is formed of a cylindrical core portion that is formed continuouslyin the circumferential direction, and is held between a front bracket 12and a rear bracket 13 from both sides thereof in the axial direction.With the above structure, the stator 2 is supported at the inner side ofthe brackets. Plural teeth (not shown) are formed on the innercircumferential side of the core back which is an inner circumferentialportion of the stator core 6. The teeth are dentate core portions thatare so formed as to project toward an inner center side in the radialdirection from the inner circumferential surface of the core back, andformed continuously in the axial direction along the innercircumferential surface of the core back. The plural teeth are at givenintervals in the circumferential direction along the innercircumferential surface of the core back. Slots (not shown) of the samenumber as that of the teeth are formed between the respective adjacentteeth. The slots are space portions for receiving the winding conductorsthat constitute the stator winding 5, and formed continuously in theaxial direction as with the teeth portion. Plural slots are arranged atpredetermined intervals in the circumferential direction. Also, a sideopposite to the core back of each slot is opened, and both ends of theslot in the axial direction are also opened. Each of the slots receivesthe winding conductor that constitutes the stator winding 5. Each of thewinding conductors is formed by a rectangular wire or a circular wire.Each of the winding conductors projects outward from both ends of thestator core 6 in the axial direction to be connected to obtain a starconnection. In this embodiment, the stator winding 5 is formed of twothree-phase windings that are electrically independent from each other.

The rotor 3 is so disposed as to face the inner circumferential side ofthe stator 2 with a gap. A rotary shaft 9 is disposed on the center axisof the rotor 3. One end side of the rotary shaft 9 is supportedrotatably by a bearing 14 at the center portion of the front bracket 12,and the other end side is supported by a bearing 15 at the centerportion of the rear bracket 13. A portion of the rotary shaft 9 whichfaces the inner circumferential side of the stator 2 is fixed into arotor core 7. The rotor core 7 is structured so that a pair of unguiformmagnetic pole cores face each other in the axial direction. Theunguiform magnetic pole cores have plural unguiform magnetic poles thatextend toward the centrifugal side in the radial direction from thecylindrical core portion, and have triangular or trapezoidal leadingends folded at right angles in directions along which those leading endsface each other. The unguiform magnetic poles are arranged at givenintervals in the rotational direction. In the case where the unquiformmagnetic poles face each other in the axial direction, the unguiformmagnetic poles are arranged between the respective unguiform magneticpoles of the unguiform magnetic pole cores that face each other. One ofthe unguiform magnetic pole cores forms an N pole. The other magneticpole forms an S pole. With the above structure, the rotor 3 has pluralmagnetic poles formed in such a manner that the polarity is alternatelydifferent in the rotational direction, that is, the N pole and the Spole are alternate. The field winding 8 is disposed on the outercircumference of the core portions which face the inner circumferentialside of the leading portions of the unguiform magnetic poles. One end ofthe rotary shaft 9 in the axial direction (end portion of the frontbracket 12 side) extends toward the outer side in the axial directionfarther than the bearing 14. A pulley 100 a is disposed on a portionthat extends toward the outer side in the axial direction farther thanthe bearing 14 on one end of the rotary shaft 9. The pulley 100 a isconnected to a pulley 120 a of the engine 120 through a belt (notshown). The other end of the rotary shaft 9 in the axial direction (theend portion on the rear bracket 13 side) extends toward the outer sidein the axial direction farther than the bearing 15. A slip ring 17 isdisposed on the outer circumferential surface of the portion thatextends toward the outer side in the axial direction farther than thebearing 15 on the other end of the rotary shaft 9. The slip ring 17 iselectrically connected to the field winding 8. The slip ring 17 isslidable in contact with a brush 16. The brush 16 supplies a fieldcurrent to be supplied to the field winding 8 to the slip ring 17. Afront fan 11 is attached onto one end of the unguiform magnetic polecore (end portion on the front bracket 12 side) in the axial direction.A rear fan 10 is attached onto the other end of the unguiform magneticpole core (end portion on the rear bracket 13 side) in the axialdirection. The front fan 11 and the rear fan 10 rotate together with therotation of the rotor 3 so that an outside air to be a cooling medium isintroduced into the interior of the machine from the exterior and thencirculated within the machine, and the outside air that has finished thecooling function is exhausted toward the exterior from the interior ofthe machine. In order to achieve the above operation, pluralthrough-holes are provided at the front bracket 12 and the rear bracket13 in order to introduce the outside air into the interior of themachine from the exterior and to exhaust the outside air toward theexterior from the interior of the machine.

A space defined by module cases 62 and 63 is formed on one side of aside surface of the rear bracket 13 (a side opposite to the frontbracket 12 side). An inverter device 50 is installed in the space. Themodule case 63 serves as a brush holder that holds the brush 16. Acommunication terminal 60 and a battery terminal 18 are exposed from themodule case 62 toward the external. The rear bracket 13 is electricallyconnected to a chassis of the automobile 200. A positive pole side ofthe inverter device 50 is electrically connected to the battery terminal18, and a negative pole (ground) side is electrically connected to therear bracket 13. The above structure has the compatibility with thegeneral vehicle alternator.

Now, a specific arrangement structure of the inverter device 50 will bedescribed. Concerning the structure of the control circuit 53 includingthe converter circuit 55 and the control power supply 54 a, there areconsiderable two types. One of the converter circuits 55 may be formedof P-channel MOSFETs 64 and N-channel MOSFETs 65. Another may be formedof only the N-channel MOSFETs 65. Herein both types thereof will bedescribed in comparison. In the inverter for outputting a large current,the N-channel semiconductor device is mainly used in order to reduce theloss of the semiconductor device at the on time. However, in thisembodiment, the control circuit 53 including the converter circuit 55and the control power supply 54 is structured as shown in FIG. 1 for thepurposes of the downsizing and the high-temperature durability in orderto mount the inverter device 50 integrally with the rotary electricmachine body 1. The structure of the control circuit 53 including theconverter circuit 55 and the control power supply 54 a as in the latteris shown in FIG. 12.

When the circuits in FIGS. 1 and 12 are compared with each other, in thecircuit shown in FIG. 12, in order to drive an N-channel MOSFET 65 a onthe higher potential side, there is required a high side power supply300 relative to a potential of an output terminal 76 which fluctuatesdue to the rotation of the motor-alternator 100. However, in the circuitof this embodiment shown in FIG. 1, in MOSFETs of the higher potentialside, a potential between the higher potential and the lower potentialcan be supplied to the gate electrodes of each MOSFET relative to thehigher potential side of the battery 150; and in MOSFETs of the lowerpotential side, the potential between the higher potential and eachlower potential can be supplied to the gate electrodes of each MOSFETrelative to the lower potential side (ground potential) of the battery150; thereby making it possible to drive the respective MOSFETs. Thismeans that, in order to drive the three-phase alternating motor, thehigh side power supply 300 for driving the MOSFET on the higherpotential side is not required in the circuit shown in FIG. 1, whereasat least three high side power supplies 300 are required in the circuitshown in FIG. 12. Moreover, an electrolyte capacitor that is relativelylarge in the electrostatic capacity is required in the high side powersupply 300 in order to hold the voltage. The electrolyte capacitorsuffers from a problem on the reliability under the high-temperatureenvironment. A relationship between the lifetime of the electrolytecapacitor and the temperature is frequently expressed by the followingrelational expression that applies the Arrhenius law.L=Lc*A ^(((TC−T)/10))where L is the lifetime at the used temperature T, Lc is the lifetime ata reference temperature T_(c), T is the used temperature, T_(c) is thereference temperature, and A is a temperature acceleration coefficient.The lifetime of the electrolyte capacitor means an increase in theinternal resistance and a decrease in the capacitance. For example, inthe case of A=2, the lifetime becomes ½ when the used temperature T ishigher than the reference temperature T_(c) by 10° C. As describedabove, the electrolyte capacitor exponentially deteriorates theperformance under the high-temperature environments. Also, it isimpossible to make the electrolyte capacitor IC-compatible, and theelectrolyte capacitor is improper for downsizing the circuit. From thisviewpoint, there is required a structure in which the electrolytecapacitor is not used in the rotating electric machine that mounts theinverter device 50 integrally with the rotating electric machine body 1.On the other hand, because the control power supply 54 a for only thenecessary control circuit 53 in the circuit of this embodiment shown inFIG. 1 steps down the output voltage of the battery 150 to generate thereference voltage, there can be provided the power supply circuit thatdoes not require the electrolyte capacitor. From this viewpoint, inorder to constitute the inverter device that improves the heatresistance using no electrolyte capacitor, it is understood that thecircuit of this embodiment shown in FIG. 1 is effective. Also, there area large number of MOSFETs that are driven by a power supply of about 10V to 14 V. From this viewpoint, since the circuit structure of thisembodiment shown in FIG. 1 can use the 14 V power supply mounted on alarge number of vehicles as it is, the MOSFET is proper for the inverterbuilt-in rotating electric machine that is applied to the 14 V powersupply vehicle.

Subsequently, the structures shown in FIGS. 1 and 12 are compared witheach other from the viewpoint of an area in which the converter circuitis mounted. In FIGS. 1 and 12, an insulating substrate 66 is formed of acircuit board where electrically conductive plates 66 b to 66 d and aninsulating plate 66 a are put together. The insulating plate 66 a ismade of aluminum nitride, silicon nitride or alumina which is aninsulating material that is excellent in the heat conductance. In thecircuit structure shown in FIG. 12, there is required that theconductive plates 66 b and 66 d of the insulating substrate 66, whichalso serve as wirings of the converter circuit, are divided into twopieces and insulated from each other in order to fix the MOSFETs at thehigher potential side and the lower potential side. As a result, it isnecessary to provide a predetermined distance between the conductiveplates 66 b and 66 d for insulation. Also, there is required an area fora wiring that connects a source electrode of the MOSFET 65 a at thehigher potential side to the conductive plate 66 d of fixing the MOSFET65 b at the lower potential side. On the contrary, in the circuitstructure of this embodiment shown in FIG. 1, because the MOSFET 64 atthe higher potential side and the MOSFET 65 at the lower potential sidecan be fixed onto the single conductive plate 66 b, the mounting areacan be reduced more than the circuit structure shown in FIG. 12 withoutthe above-mentioned restriction. Also, in the motor-alternator 100 ofthis embodiment, the importance of the temperature management of the MOSsemiconductor that is a main heating part is high because themotor-alternator 100 is used under the high-temperature environments. Inorder to manage the temperature with higher precision, it is essentialto locate a temperature sensing thermistor 57 on the conductive plate 66b on which the MOS semiconductor is fixed. In the circuit shown in FIG.12, two thermistors 57 are required because the conductive plates onwhich the MOS semiconductors at the higher potential side and the lowerpotential side are fixed are separated from each other. On the otherhand, one thermistor 57 may be provided in the circuit structureaccording to this embodiment shown in FIG. 1. Even if an area necessaryto locate the thermistor 57 is not taken into consideration, the circuitstructure of this embodiment shown in FIG. 1 can reduce the mountingarea more than the circuit structure shown in FIG. 12.

Accordingly, this embodiment, in which the circuit structure shown inFIG. 1 is applied, solves problems occurring when the inverter device 50is integrally mounted on the rotating electric machine body 1, that is,problems such as the downsizing and the high-temperature durability.

Hereinafter, a specific arrangement structure of the inverter device 50will be described with reference to FIG. 2. In FIG. 2, reference numeral64 denotes each P-channel MOSFET, 65 is each N-channel MOSFET, 66 is aninsulating substrate, 61 is a radiation conductive plate, 67 is anoutput terminal, 70P and 70N are power supply wirings, 71 is a positivepole side power terminal, 72 is a control circuit board, and 51 is acontrol IC (control unit). Also, reference numeral 60 denotes acommunication terminal, 74 is a wiring for connects the source electrodeof the P-channel MOSFET 64 and the power supply wiring 70P, 75 is awiring that connects the source electrode of the N-channel MOSFET 65 andthe radiation conductive plate 61, 76 is a wiring that connects anelectrically conductive plate of the insulating substrate 66 and theoutput terminal 67, 73 is a rotation sensor, and 77 is a wiring thatconnects a P-channel MOSFET as a diode 68 and the power supply wiring70P. Further, reference numeral 78 denotes a wiring that connects theinsulating substrate and the power supply wiring 70N, 69 denotes awiring that connects the source electrode of the N-channel MOSFET 69 andthe radiation conductive plate 61, 80 is an aluminum wire for connectingthe control circuit board 72 to the P-channel MOSFET 64 and theN-channel MOSFETs 65, 69, respectively.

As shown in FIG. 2, the control unit 51 and the rotation sensor 73 aredisposed in an upper half of a space within the module cases 62 and 63,and the module unit 52 is disposed in a lower half of the space. Thedrain electrodes of the P-channel MOSFET 64 and the N-channel MOSFET 65are connected to the conductive plates of the insulating substrate 66 inwhich the conductive plates are bonded to the insulating plate. Thesource electrode of the P-channel MOSFET 64 and the power supply wiring70P are connected by the wiring 74. The source electrode of theN-channel MOSFET 65 and the radiation conductive plate 61 that alsoserves as the ground wiring are connected by the wiring 75. Theconductive plates of the insulating plate 66 and the output terminal 67are connected by the wiring 76. With the above structure, the mountingstructural bodies shown in FIG. 1 (arms of the respective phases whichconstitute the bridge circuit) are disposed radially so as to extend inthe radial direction in the lower half of the space within the modulecases 62 and 63. Reference U1, U2, V1, V2, W1 and W2 attached toreference numeral correspond to the respective phases of the two statorwirings 5. In this embodiment, the mounting structural bodies shown inFIG. 1 are arranged in such a manner that the mounting structural bodiesof the same phase are adjacent to each other. The output terminal 67 isconnected to a phase winding corresponding to the stator wiring 5. Inthis embodiment, a description is given of the structure in which sixinsulating substrates 66 are mounted, and the stator windings 5 of twosystems are provided. In the case where the stator winding 5 of onesystem is provided, the arms of the respective phases which constitutethe bridge circuit may be disposed in such a manner that the arms of thesame phase are arranged in parallel and connected to the phase windingscorresponding to the stator windings 5.

The output terminal 67, the power supply terminal 71 and the powersupply wirings 70P, 70N are embedded in the module case 63 so as to beexposed on the surface of the module case 63. A part of the module case63 adheres to the radiation conductive plate 61.

Plural electronic circuit elements that constitute the control circuit53 and the driver circuit 54 in the control unit 51 are integrated intoone IC chip. The control IC 51 is disposed on the control circuit board72 and electrically connected to the control circuit board 72. TheP-channel MOSFET 64 and the N-channel MOSFETs 65, 69 in the module unit52, and the control circuit board 72 are electrically connected to eachother by the aluminum wire 80. The control circuit board 72 is alsoelectrically connected with the communication terminal 60 and therotation sensor 73. The communication terminal 60 is used forcommunication with the engine control device 140 and connected with anLIN. The rotation sensor 73 detects the rotational speed of themotor-alternator 100 by sensing the magnetism of a magnetic pole disk 4that is disposed at an end of the rotary shaft 9.

The P-channel MOSFET 68 makes its gate electrode identical in potentialwith its source electrode so as to be used as a diode. As a result, thedrain electrode of the P-channel MOSFET 68 and the drain electrode ofthe N-channel MOSFET 69 are joined to the conductive plate of theinsulating substrate 66 f as the MOSFET of the converter circuit 55.

The control IC 51 has the function of the regulator IC of theconventional vehicle alternator. As a result, the control IC 51 servesas the regulator IC. As described above, it is necessary to improve thehigh-temperature durability in the rotating electric machine on whichthe inverter device is integrally mounted. In addition, it is necessaryto reduce the heating of the semiconductor elements that constitute theconverter circuit 55 to suppress a rising temperature of the inverterdevice. In particular, in the case where the inverter device is used foridling stop, a time required for motor driving when the engine 120 isrestarted is less than one second, and most of the running time of themotor-alternator 100 functions as the alternator. From the above fact,the loss reduction at the time of electric power generation is effectivein suppression of the rising temperature of the inverter device.

In the case where the synchronous rectifying function is not used,rectification is conducted by a diode that is installed in the MOSsemiconductor device of the converter circuit 55. For example, in thecase where a current 50 A passes through into the diode, a built-inpotential of about 1V is required with the result that heating of 50A×about 1 V=about 50 W occurs. On the contrary, because theon-resistance of the MOSFET can be set to about 3 mΩ, the heating in thecase where a current of 50 A passes through the MOSFET becomes about 3mΩ×(square of 50 A)=about 7.5 W. The heating value of the diode is about7 times as large as the heating value of the MOSFET. As is understoodfrom this fact, to conduct synchronous rectification at the time ofelectric power generation is every effective in the suppression of therising temperature of the inverter device. As another countermeasureagainst the case where heating is large, there is a method of increasingthe mounting area of the semiconductor device in the converter circuit55. However, taking the heating value of the diode into consideration,the area of about seven times is required in order to offset the heatingof about seven times, and this method is improper from the viewpoints ofdownsizing and the cost reduction. For the above reasons, in thisembodiment, the synchronous rectifying function is provided to thecontrol IC 51.

In order to mount the control circuit 53 on the rotating electricmachine body 1, it is essential to integrate the electronic circuitelements that constitute the control circuit 53 as with the control IC51. However, a long developing period of time and high developing costsare taken for development of the IC. For that reason, a device thatsuppresses the developing costs and flexibly deals with various vehiclesis required. Also, it is desirable that the control IC 51 can alsoflexibly deal with a change in the semiconductor device used in theconverter circuit 55 and a change in the specification of the statorwinding 5 of the motor-alternator 100. In this embodiment, in order toenhance the flexibility, an MP 53 d, a RAM 53 m and a ROM 53 n aremounted on the control IC 51. By rewriting the memory contents in theROM 53 n, it is possible to change parameters for controlling the powergeneration or parameters for controlling the drive current at the timeof starting the motor according to the battery voltage, the temperatureor the engine rotational speed.

Subsequently, the operation of the motor-alternator 100 according tothis embodiment will be described with reference to FIG. 11. Initialsetting is executed in Step S1, and an electric power generation controlroutine is executed in Step S2. In the electric power generationcontrol, the field control executed through the use of the synchronousrectification control, the battery voltage, the command battery voltageand the temperature detected by the temperature sensor circuit. In StepS3, it is judged whether idling stop, that is, the engine 120 stops, ornot, and if judgment is not the idling stop, processing is advanced toStep S2, and the electric power generation continues. If the judgment isthe idling stop, a standby state setting for restarting the engine 120is executed in Step S4. As one operation of the standby state setting,there is an operation where a predetermined field current is allowed topass through the field winding 8 in advance so that a torque occursimmediately at the time of restart. The predetermined field currentvaries according to the electric constant of the field winding 8 or theamount of torque necessary to restart the engine 120. In the control IC51 that mounts the MP 53 d, the RAM 53 m and the ROM 53 n, the standbystate setting can be dealt with by changing a variable of the memory.

In Step S5, it is judged whether there is a restart command of theengine 120, or not. When there is no restart command of the engine 120,the standby state continues, and when there is the restart command, theprocessing is advanced to Step S6. In Step S6, the motor drive routineis executed. The rotational speed of the motor-alternator 100 isdetected in Step S7, and the detected rotational speed is compared witha targeted rotational speed Nref. In the case where the detectedrotational speed is equal to or less than the targeted rotational speedNref, a set value of the field current is maintained in Step S9. In thecase where the detected rotational speed exceeds the targeted rotationalspeed Nref, a field magnetic current reduction routine is executed inStep S10, and the field magnetic current is reduced down to apredetermined value. Then, it is judged whether the engine 120 isrestarted, or not, in Step S11. The restart judgment in Step S11 is madeby, for example, a command signal from the engine control device 140.After the engine 120 starts, the processing is advanced to the electricpower generation control in Step S2, and when the engine 120 does notstart, the processing is returned to Step S6, and the motor driveroutine continues. If the engine 120 starts at a high rotational speedwhile the field current is kept large, and a large electric power israpidly generated, a rapid load fluctuation of the engine 120 occurs.Step S10 is a routine that is executed to reduce the field current andto prevent from such a rapid load fluctuation of the engine.

Also, this embodiment desirably applies not a system of bringing theswitching semiconductor device into operation at a carrier frequency ofseveral kHz as the PWM control system, but a system of driving the motorwith one on/off operation per one cycle as the motor drive system.

In the inverter, a surge voltage dependent on a wiring inductance ofcausing a change in turn off speed of a current and a current value isapplied to the switching semiconductor device. As means for reducing thesurge voltage, there is a method of reducing the wiring inductance bydisposing the electrolyte capacitor with the capacity of about 0.5 mF to10 mF between the battery and the ground. However, in this embodiment,it is difficult to use the electrolyte capacitor with a large capacityfrom the viewpoints of the operation environments and downsizing.

To reduce the surge voltage, there may be proposed that a turn off speedof the current is made gentle. In this point, in the case of using thePWM control system, if the turn off speed of the current is made gentle,the loss in the switching semiconductor element which occurs every timeswitching is conducted cannot be ignored. However, in the system ofdriving the motor with one on/off operation per one cycle is applied,the amount of loss caused by switching per unit time can be reduced.

The system of driving the motor by bringing the switching semiconductordevice in operation with one on/off per one cycle can be performed bythe following control: controlling the gate voltage output of theswitching semiconductor device in synchronism with the a hole sensoroutput that switches to high and low every 180° according to an anglebetween the rotor windings and the stator windings of the respectivephases as shown in FIG. 3. In this example, the hole sensor can alsoserve as the rotation sensor 73. The hole sensor outputs H_U₁, H_V1, andH_W1 shown in FIG. 13 have a relationship different in the phase by 120°with respect to the respective outputs. Also, a gate signal Ulg1 becomesa gate off voltage due to the rising of the hole sensor output H_U1. Andthe gate voltage is controlled so as to generate the gate on-statevoltage of the switching semiconductor device of the upper arm of thesame phase after a delay time. In this example, the delay time isprovided because the switching semiconductor devices of the upper andlower arms are prevented from turning on at the same time.

The application of the above motor drive system does not require thearrangement of the capacitor with a large capacity between the batteryand the ground as shown in FIG. 14, and an inverter circuit can beconstituted by provision of only a capacitor with a small capacity ofabout 1 μF which filters the noises from a direct current cable.

The above-mentioned motor-alternator 100 according to this embodimenthas the following advantages.

1) The driving power supply of the MOSFET and the electrolyte capacitorat the higher potential side are not required, and the mounting area canbe reduced and the high temperature resistance can be improved (refer toFIG. 15).

2) The circuit mounted area of the converter circuit 55 can be reduced.

3) A reduction in the size of the semiconductor devices in the convertercircuit 55 and a reduction in the costs can be effected by the heatingreduction effect of the synchronous rectification.

4) The electronic circuit elements that constitute the control circuit53 and the driver circuit 54 are integrated into the control IC 51,thereby making it possible to reduce the size.

5) The MP 53 d, the RAM 53 m and the ROM 63 n are mounted on the controlIC 51, thereby making it possible to suppress the costs and to flexiblydeal with vehicles with different engines or different electric powergeneration systems.

6) The electrolyte capacitor with a large capacity which should bearranged between the battery and the ground is not required, and theinverter can be constituted by only a capacitor with a small capacitywhich filters the noises from a direct current cable, thereby making itpossible to downsize the device.

Therefore, according to the motor-alternator 100 of this embodiment, theintegration of the rotating electric machine body 1 with the inverterdevice 50 can be realized by substantially the same size as that of thenormal vehicle alternator while the costs are suppressed.

In the background art of the present specification, there is describedthat parts which are simply mounted are necessary in spread of theidling stop system. The present invention provides the motor-alternator100 having the inverter compatible with existing alternators, as a partnecessary for realizing the idling stop system. The present invention ismade to realize the idling stop system that is substantially identicalwith the existing vehicle layout, but when the present invention isconsidered as the system, it is necessary to combine the system with alead battery that allows a large current output in a short period oftime. For example, a current output from the battery 150 at the time ofrestarting the engine is about tenth of several seconds, and becomes 200to 400 amperes of the same degree as that in the case where the enginestarts due to the stator. When the battery voltage becomes equal to orless than 10 V in the battery voltage drop at the time of outputting alarge current, there is a fear that the stable operation of a devicesuch as an audio device or a car navigation system is impeded duringthat period. There is a method of arranging the lead batteries inparallel in order to prevent the voltage drop, but there arises a newproblem on the assurance of the mounting space. This problem can besolved by a winding lead battery that is disclosed in, for example,Japanese Patent Application No. 2004-133693. The winding lead batterydisclosed in the above Japanese Patent Application No. 2004-133693 has aperformance that can hold the battery voltage to 10 V or higher at thetime of outputting a large current in a short period of time with avolume that is equal to or less than that of the conventional leadbattery. The combination of the winding lead battery with themotor-alternator of the present invention can provide an idling stopsystem that is substantially identical with the existing vehicle layout.

As described above, according to the present invention, even in acompact vehicle with a limited vehicle mounting space, the idling stopsystem can be realized without remarkably changing the layout within theengine room.

1. A power converting device comprising: a module unit having a powercontrol circuit; and a control unit that controls the operation of thepower control circuit, wherein the power control circuit is configuredby connecting a plurality of the following series circuits in parallel,each of the series circuits includes a P-channel MOS semiconductordevice disposed at a higher potential side and an N-channel MOSsemiconductor device disposed at a lower potential side which areelectrically connected in series, and the control unit comprises: acontrol circuit that outputs command signals for driving the P-channelMOS semiconductor devices and the N-channel MOS semiconductor devicesrespectively; and a driver circuit that outputs drive signals fordriving the P-channel MOS semiconductor devices and the N-channel MOSsemiconductor devices to those MOS semiconductor devices respectivelyupon receiving the command signals outputted from the control circuit,wherein the control circuit comprises a plurality of first electroniccircuit elements and the driver circuit comprises a plurality of secondelectronic circuit elements, the plurality of first electronic circuitelements are integrated and mounted on a first substrate and theplurality of second electronic circuit elements are integrated andmounted on a second substrate.
 2. A power converting device according toclaim 1, wherein the power control circuit controls a power that issupplied from a vehicle power supply or a power that is supplied to thevehicle power supply.
 3. A power converting device according to claim 2,wherein the control circuit has a power source on the basis of the powerthat is supplied from the vehicle and operates to output the commandsignals for driving the P-channel MOS semiconductor devices and theN-channel MOS semiconductor devices.
 4. A power converting deviceaccording to claim 1, wherein the P-channel MOS semiconductor devicesand the N-channel MOS semiconductor devices are field effecttransistors.
 5. A power converting device according to claim 4, whereineach pair of the P-channel semiconductor device and the N-channel MOSsemiconductor device have a drain electrode thereof connected toconductors of the same potential, and are mounted on the conductors. 6.A power converting device according to claim 1, wherein the control unitincludes a rewritable memory.
 7. A power converting device according toclaim 1, wherein the control unit comprises an adjusting device foradjusting the operation speeds of the P-channel MOS semiconductordevices and the N-channel MOS semiconductor devices, and a memory devicethat stores information for setting the operation speed therein, and theadjusting device adjusts the operation speeds of the P-channel MOSsemiconductor devices and the N-channel MOS semiconductor devicesaccording to the operation speed information from the memory device. 8.A power converting device according to claim 5, wherein the conductorhas one temperature sensing element for sensing the temperatures of theP-channel MOS semiconductor devices and the N-channel MOS semiconductordevices.